Rainer (If you are still around)

I would guess that the man in the song is fond of the gargle as we say in Dublin (Alcohol that is).

In the first verse he is in "The Horrors" or the DTs, i.e his nervousness is induced by alcohol from the night before.

I would regard the song as being mostly a bit of nonsense, do't bother trying too hard to understand it.

By the way Nelson's Pillar was blown up in 1966 the 50th anniversary of the 1916 rising.